The Effects of Cisplatin on the Expression of Calpain in Mouse Cochlear Hair Cell in Vitro / 听力学及言语疾病杂志

ABSTRACT

Objective To investigate the effects of cisplatin on the expression of calpain in mouse cochlear hair cells in vitro ,and to explore the mechanism of cisplatin-induced apoptosis in mouse cochlear hair cells .Meth‐ods A total of 600 cochlear basilar membranes isolated from Kunming mice at postnatal day 3 were cultured for 24 hours ,then randomly divided into control group and 3 cisplatin groups (4 μg/ml ,8 μg/ml and 16 μg/ml) .Each group contained 150 basilar membranes .Four groups were continually cultured for another 24 hours .Hoechst 33258 staining was used to detect the apoptosis of cochlear hair cell .Immunofluorescent staining and Western blot were carried out for detecting the expressions of calpain 1 (μ-calpain) and calpain 2 (m-calpain) in mouse cochlear hair cells .Results The percent of apoptotic hair cells in the three cisplatin groups (15 .63% ± 0 .20% ,38 .40% ± 2 .64% and 64 .24% ± 0 .05% ,respectively) was greater than that of in the control group (5 .55% ± 0 .12% ) , showing a clear dose-response relationship (P<0 .01) .Furthermore ,the expressions of μ -calpain and m -cal‐pain in different cisplatin groups were increased ,and m -calpain expression was great remarkably with increased concentration of cisplatin (P<0 .01) .Conclusion Our results suggest that cisplatin can induce the apoptosis in mouse cochlear hair cells by regulating calpain pathway .This may play a role in the cisplatin-induced ototoxicity .